llvm dev - Aug 2019 - [lld] section attributes lld can use to safely drop a section from obj files

Hello llvm\lld,


The autlolink feature in swift appends a section to the obj files
(.swift1_autolink_entries) that is later need to determine what t link
against in the final linked binary.

I am trying to get rid of these section in the final linked binary at link
time. I understand this could be done with (llvm-objcopy
 --remove-section=.swift1_autolink_entries) but would like have the linker
do it.

Is there an attribute I can set in that section that the linker can safely
drop such a section?

Thank you,
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I guess I will ask the obvious question: Can Swift be migrated to the
.deplibs feature that was added to ELF LLD instead?

I don't know the answer to your original question, unfortunately.

On Tue, Aug 6, 2019 at 11:48 AM Sameer Abu Asal via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hello llvm\lld,
>
>
> The autlolink feature in swift appends a section to the obj files
> (.swift1_autolink_entries) that is later need to determine what t link
> against in the final linked binary.
>
> I am trying to get rid of these section in the final linked binary at link
> time. I understand this could be done with (llvm-objcopy
>  --remove-section=.swift1_autolink_entries) but would like have the linker
> do it.
>
> Is there an attribute I can set in that section that the linker can safely
> drop such a section?
>
> Thank you,
>
>
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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Yeah, there is an attribute you can use to tell the linker to ignore a
section, SHF_EXCLUDE. it was used for some DWARF stuff here:
https://reviews.llvm.org/D52303

On Tue, Aug 6, 2019 at 11:52 AM Reid Kleckner via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> I guess I will ask the obvious question: Can Swift be migrated to the
> .deplibs feature that was added to ELF LLD instead?
>
> I don't know the answer to your original question, unfortunately.
>
> On Tue, Aug 6, 2019 at 11:48 AM Sameer Abu Asal via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hello llvm\lld,
>>
>>
>> The autlolink feature in swift appends a section to the obj files
>> (.swift1_autolink_entries) that is later need to determine what t link
>> against in the final linked binary.
>>
>> I am trying to get rid of these section in the final linked binary at
>> link time. I understand this could be done with (llvm-objcopy
>>  --remove-section=.swift1_autolink_entries) but would like have the
linker
>> do it.
>>
>> Is there an attribute I can set in that section that the linker can
>> safely drop such a section?
>>
>> Thank you,
>>
>>
>>
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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